The present invention concerns an electromagnetic actuator device.
In such devices a coil unit (typically cylindrical in cross-section) is provided on a stationary yoke unit such that it encloses a first yoke section of the yoke unit and when energised introduces a magnetic flux into the yoke unit. This coil magnetic flux then interacts across a (working) air gap with the armature elements, which in turn execute the desired actuator movement, i.e. a positioning movement for an output-side positioning partner. Here it is on the one hand presupposed to be a generic feature, in the manner of a laterally outwardly mounted coil, to provide the coil unit with the related first yoke section spaced apart from the second yoke section forming the air gap, i.e. to provide the air gap completely outside the first yoke section. While this material originates from the applicant's internal, unpublished prior art, it is on the other hand, in turn a generic feature, presupposed to be of known art, that the coil unit at least partially, i.e. in some sections, encloses the (working) air gap (and in this respect also interacts directly with the armature agents); this corresponds to the functional operation of typical electromagnetic actuators provided axially along the linear direction of movement of the armature.
Both generic principles have certain advantages in each case; thus, for example, the approach first cited enables by means of the activation (energisation) of the coil unit a specific influence of the flux in the magnetic flux circuit formed by the yoke unit, typically having a plurality of arms. In contrast it can here be established as potentially disadvantageous that the coil efficiency of the coil unit (as a result of the occurrence of undesirable stray fields) is non-optimal, moreover, concepts such as the outwardly mounted coil have the problem of possible transverse forces acting on the armature unit as a result of the coil magnetic flux, i.e. forces (or force components) which not (only) extend along the linear armature direction of movement, but in addition cause a tendency to tilt, and in this respect cause wear; in particular these reduce the suitability of such devices for low wear continuous operation.
In contrast the generic principle of the armature unit enclosed or covered by the coil unit is less affected by such transverse forces, however, for example, the design-related options for introducing additional magnetic flux into the armature unit (via the working air gap) are limited and are primarily determined by the coil dimensions. As a result disadvantages occur in turn with regard to the utilisation of and/or adaptation to build spaces that are available, possible thermal or winding losses or similar disadvantages. In addition, for example, when utilising such an electromagnetic actuator device for purposes of valve control, the enclosure of the armature unit, in this respect operating effectively on the valve, by means of the coil unit offers the problem of limited supply and removal options for a particular fluid that is to be influenced by the valve.
The object of the present invention is therefore to improve an electromagnetic actuator device with regard to rendering the magnetic flux in the stationary yoke unit more flexible, in particular with regard to creating the possibility of adapting such an electromagnetic actuator device (potentially at the same time as optimising its efficiency) to build space limitations and/or of minimising possible wear.